1. Field of the Invention
The invention generally relates to an image forming apparatus, an authentication system, an authentication control method, an authentication control program, and a computer-readable recording medium having such an authentication control program embodied therein, and particularly relates to an image forming apparatus, an authentication system, an authentication control method, an authentication control program, and a computer-readable recording medium having such an authentication control program capable of carrying out authentication of users.
2. Description of the Related Art
Many offices use shared image forming apparatuses having authentication functions to authenticate users so that the image forming apparatuses are only used by authenticated users. Further, these image forming apparatuses include authentication functions and access control functions, and the combination of such functions can control users' accessibilities to different functions of the image forming apparatuses.
It is desirable to prepare a database for managing authentication information of users (hereinafter called a “user DB”) for the image forming apparatuses in order to fully perform the authentication function. Some offices may have several image forming apparatuses. On the corporate scale basis, some companies have several thousand to several tens of thousands of image forming apparatuses. If the user DB is distributed to such numerous image forming apparatuses, not only may user DB maintenance activity per se become cumbersome, but the usability of resources (e.g., HDD (Hard Disk Drive)) in the image forming apparatuses may be degraded.
Japanese Patent Application Publication No. 2009-071409, for example, discloses the image forming apparatus in which the authentication functions and the user DBs for the image forming apparatuses in the office are provided in an external computer (i.e., authentication server). In the image forming apparatuses having this configuration, the authentication information of a user input via an operations panel is transferred to the authentication server via a network. The authentication server then compares the transferred authentication information of the user with the information of the user stored in the user DB to authenticate the user. Thereafter, the authentication server sends a response including the authentication result to the image forming apparatus via the network. With the above system configuration, the user DB maintenance activity may be simplified and the usability of the resources in the image forming apparatus may be improved.
However, with such a system configuration (i.e., an authentication server is assigned to authenticate users), users may have difficulties in logging into the image forming apparatuses despite the fact that they are functioning properly if some kind of communication trouble occurs in the network between the image forming apparatus and the authentication server or if the authentication server itself is not working properly. As a result, the users may be unable to access the image forming apparatuses, which may further interrupt efficiency in their work duties. Notice that more communication problems may occur if the image forming apparatuses and the authentication server are connected via a wide area network (WAN) such as the Internet.